1. Technical Field
The present invention relates in general to networks and, in particular, to a method and system for routing communication between nodes of a network containing multiple nodes. Still more particularly, the present invention relates to a network in which communication between nodes of a system area network (SAN) is filtered by traffic type, for example, to avoid errors arising from multiple nodes sharing the same node identifier.
2. Description of the Related Art
A system area network (SAN) is a collection of interconnected processor and peripheral nodes that operate in concert as a data processing system. The SAN topology advantageously permits large data processing systems customized to the processing, storage and I/O requirements of particular installations to be readily constructed through the interconnection of desired numbers of processor and peripheral nodes via backplane connections or inter-cabinet cables.
To promote reliable, efficient communication, a SAN generally logically and physically isolates processor buses and input/output (I/O) buses in separate nodes. Communication between the processors and peripherals in a SAN must therefore be routed between nodes, for example, utilizing unique node identifiers (IDs) assigned by firmware at system startup.
The conventional method of routing communication in a SAN is subject to errors if, following system startup, two SANs are interconnected, for example, by an inter-cabinet cable. Errors arise because the node IDs assigned in each of the smaller SANs may not be unique throughout the combined system. As a result, communication in the combined system may be routed incorrectly, possibly causing data corruption and/or other undesirable errors.
The present invention therefore recognizes that it would be useful and desirable to provide an improved method and system of inter-node communication in a SAN in which all of the nodes may not have unique node IDs.